Furnace for steam-boilers.



BIG. MILLS.

FURNAGE FOR STEAM BOILERS. urmouzon FILED Mia. 14; 1910.

1,041,325., Patented Oct. 15,1912.

3 SHEETS-SHEET 1.

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FURNACE FOB STEAM BOILERS. APPLICATION FILED An. 14 1910.

Patented 0ct.15,19 12;

3 SEEBTS-SKBET 2.

. x/v Vii/V797? E. G. MILLS. FURNQQB FOR STEAM BOILERS. AnPriiiATIoNFILED APB..14, 1910.

Patented Oct. 15, 1912.

3 SHEETS-SHEET 3.

. inarnn u ii FURNACE FOR STEAM-BOILERS.

enses.

To all whom it may concern:

Be it known that I, EDGAR Conis'ron MILLS, consulting mechanicalengineer, a subject of the King of the United Kingdom of Great Britainand Ireland, and resident of Manchester, in the county of Lancaster,England, have invented new and useful Improvements in Furnaces forSteam-Boilers, of which the following is a specification.

My invention aims at the recovery of heat usually lost in radiationthrough the linings of external furnaces for steam boilers and also atpromoting secondary combustion; and it consists in the main of a systemof cells or pipes formed or embedded in the lining or walls of suchfurnaces, through which air previously partially heated or not iscirculated and finally delivered by suitable orifices into the furnacechamber over the fuel bed. When such air is admitted over the firebedthe delivery orifices are preferably inclined in the direction of thedraft and are placed in such positions as best to bring the air'intointimate contact with the volatile gases and carbon nionoxid so as topromote their combustion. Some of such orican be placed over or in orbehind the bridge or still further in the fine.

My invention is also equally applicable to furnaces whose air supply isobtained either by chimney draft, induced fan draft, by front fan draftor by steam induction jets.

In the case of external boiler furnaces, mechanically fe d or otherwise,having clinker pits I utilize the otherwise waste heat in the clinker bysurrounding it with a chamber through which air is passed on its way tothe before described cells or pipes. By this means extremes oftemperature in the fire-brick cells or pipes are avoided.

In the accompanying drawings Figure I is a longitudinal section of anexternal furnace constructed in accordance with my invention shown asapplied to an ordinary two-flue Lance-shire type of boiler. Fig.

II gives half cross section and half front elevation ofthe same. Fig.III is a part longitudinal section taken through the center of one ofthe boiler internal fines, 6.

pm the line to m Fig. II. Fig. IV is a cross section of a furnacesuitable for a single fined boiler and for boilers of the type de-Specification of Letters Patent.

Application filed April 14, 1910. Serial No. 555308.

Patented. (let. 11

scribed and. illustrated in the Pat 1i #989,270, granted i rpril llth,1911 to .f Lester and myself, the half-sections bein taken on lines ora: and y g Fig. V. Fig. is a longitudinal section of the 51131163, takenon the line 2 2 Fig. IV. 1 shows de tailed views in plan and elevation.of the bricks in having recesses formed therein.

Similar letters or fi ures of reference in the various figures refer ththe san'ie parts.

A is av boiler shell with its front plate (5 and internal lines a a. Thebrickwork furnace B formed with sides and arched roof, having ashpit b,firebars Z) and firing door b is built externally to and in front of theboiler A. The aslipit may be open for natural daft or closed as shown bythe door I) when. a front fan is used. in which case the cleft isregulated by the wing valve Zf admitting air from the underground airduct C by the sidebox c as seen in Fig. H. The wing valve 6' is operatedby the lever 1 either by hand or automatically by the firedoor whenopened and closed.

D the ordinary blowoil pit, and access to it and the cleaning out door Eis ohtaircd by the space 6 resulting from the formation of the ashpit7), which, as sho a, is terminated by the inclined plate 6. This plate,however, forms no part of my present invention Cells or pipes l? areformed or embedded in the brickwork of the walls and roof of the furnaceB. Each of the longitudinal. cells connected by a branch to an outerdistributing pipe or trunk g which in turn is connected to a supply duct(l in which mounted a controlling wing valve operated automatically orotherwise.

From each of the cells 1* a suitable number such as three or moreoutlets f are formed and coincident with each of them an inclinedorifice f is provided in the inner brickwork lining. The cells arepreferably made in, short lengths and not jointed, the joints f beingleft slightly ooen to allow of freedom of expansive nimcnuani.

may be made of iron or other Sllli'l'il'llfi inetal of the furnace gasestoward the outlet to the flue or lines a. The orifices are placed abovethe fuel bed as shown.

In some cases it is desirable to deliver air over or even beyond thefirebridge and this is shown in Fig. III in which the orilice ororifices f" are shown situated so as to deliver air above and beyond thebridge H.

The air supplied to the cells by the duct G may be impelled by a fan ormay be induced by natural or other draft and it may be cold or partiallyheated before it enters the cells. Thus in the construction shown inFigs. IV and V the air for the cells is drawn through and from theashpit b by way of the aperture L controlled by the valve Z or fromother suitable source, the ashpit b and aperture L taking the functionof the duct Gr, Figs. I and II. It is then passed through the space Zsurrounding the clinker pit M from which it abstracts heat and thencepasses by passages N, which are preferably provided on both sides of theclinker pit M, to the cells F. By this means the air is heated by wasteheat before it enters the cells, the object and advantages beingotherwise similar to those already described. In this form the box 0 isprovided under the ashpit for extracting the ashes by the door 0 and thebox 1 for extracting the clinker by the door 1) while the door 3) isclosed. By this means the clinker can be ex tracted while the furnace isat work.

The nozzles f are formed as shown in Fig. 1V1. Two bricks is are moldedeach with a-recesstapered one way as shown or it may be tapered in depthas well, but in any case the outlet is smaller than the inlet 7c. Thetwo bricks are built in with their recesses adjoining so as to form onethrough tapered passage. The object is to maintain a good outletvelocity and to allow a lower velocity in the cells and passags.

'Iheoperation of the invention is as follows :The total heat ofv bothprimary and secondary combustion may be divided into radiant heat andconveyable heat. Most of the former and some of the latter is notdirectly available in the boiler fiues for evaporative purposes, as itis taken up and dissipated by the furnace brickwork 1n the case ofordinary external brick furnaces. In my invention the radiant heatabsorbed by the inner layers of the lining is thereby transformed intoconveyable heatand is largely transmitted to the air in the cells F and.nozzles F. This air is thenat such temperature as to make it eminentlysuitable for secondary combustion for which purpose it is used bypassing from the nozzles f into the interior of the furnace, a furtheradvantage being that the main body of the brickwork is protected fromexcessively high temperatures.

In hand fired furnaces the air permitted to enter by the nozzles iscontrolled by the valve g to suit the excessive variations in, thedemand for oxygen for secondary comcooling surfaces, and the intenselyhot gases pass with little or no heat loss into the boiler Hues, theretogive up their heat to the water. \Vith such furnaces the diameter of theinternal fines of boilers of the Lancashire type may be considerablyreduced.

The external furnaces herein described are applicable to any form ortype of steam boiler and also for use with or without forced, induced orother method of obtaining draft.

I am aware that air spaces and separate cells in brickwork settingssurrounding in-' ternal furnaces have previously been used, also thatheated air from them has been passed into the said furnaces forcombustion purposes above and into the fire and from and beyond thebridge, and that in external furnaces passages for air have been formedin the brick settings, but

Having now described my invention and in what manner the same is to beperformed, I declare that what I claim as new' and desire to secure byLetters Patent. is

In combination a steanrboilerj'a furnace external to said steam-boilerfor providing; heat for steam generation in such boiler, 'a casing forsaid furnace having walls and roof 'inclosing a chamber forming by itslower part a fuel-chamber to hold a firebcd and by its upper part asecondary coinbustion-space for secondary combustion above the fire-bedin said fuel chamber so that both the fuel chamber with the firebedtherein and the secondary combustionspace for secondary combustion arewholly free of contact of water-cooled plates and having within thewalls and roof a plurality of air-cells each extending in the directionof and for the greater part of the length of the furnace from front toback and spaced from one another and with a plurality of orifices foreach air-cell exair-cells whereby air will pass to said aircells andbeing heated therein by absarption presence of two witnessegthis sixthday of of he l p s thence -hmn'g-h said 0ri- April 1910.

fices into the secondar cQmblistioms ace 1 for secondary colnhu si mabove, the %18. EPGAR GONISION MILLD' 5 bed in the fuel-(gha m fir inSaid chamber. Witnesses:

In testimony, that I claim the foregoing HOWARD GHEETHAM, m myinvention, I have signed my name in RUTH MAGDALENE vVILsoN.

